Viruses which induce tumors in mammals are quite widespread. Indeed, there are over sixty-eight types of human papillomaviruses (HPV) alone which can induce the production of tumors. Some of these HPV's have been associated with benign tumors, such as common warts, while others have been strongly implicated as etiologic agents in dysplasia and carcinomas in the oral and genital mucosa of the infected mammal. Other types of viruses which can result in tumors include various RNA viruses as well as herpes viruses.
Recently, it has also been observed that individuals with depressed immune systems, such as sufferers of Aquired Immune Deficiency Syndrome (AIDS), are prone to human papillomavirus infections which can result in tumor growth over their entire bodies, resulting in great mental and physical distress to the afflicted individual.
Current modalities for the treatment of viral-induced tumors involve the removal of the tumor by either: (1) surgical intervention (laser or operative); (2) the application of organic acids, such as glacial acetic acid and/or salicyclic acid, to "burn" the tumor away; (3) the injection into the tumor of an anti-tumor vaccine prepared from ground tumors; and, to a lesser extent, (4) the application of a drug treatment (such as podophyllin, 5-FU and interferons).
While being useful for removing the viral-induced tumor, the current treatment modalities presently used nonetheless suffer from one or more of the following drawbacks: (1) they can result in the destruction of healthy uninfected tissue; (2) they can result in scarring and disfigurement; (3) they can result in discomfort to the mammal being treated thereby; and (4) they do not always result in the destruction of latent viral DNA which may be maintained in surrounding tissues. Furthermore, with these treatments, patients have suffered from significant systemic side effects, incomplete resolution and frequent recurrences of the tumors.
It has also been disclosed to use phototherapy for removing laryngeal papillomatosis tumors. While such phototherapy reduced tumor growth by about 50%, it also resulted in a generalized skin photosensitivity for at least six weeks, as well as other minor reactions. Furthermore, despite the apparent success of this technique, the presence of latent viral DNA is nonetheless still maintained in the surrounding tissues.
U.S. Pat. No. 5,073,630 discloses a polymeric anhydride of magnesium and proteic ammonium phospholinoleate with antiviral, antineoplastic and immunostimulant properties. This antiviral agent was produced in the cell-free filtrate of a selected line of Aspergillus sp. However, that compound is insoluble in water and possesses a high molecular weight (316,000 daltons).
Accordingly, it can be seen that there remains a need for prophylactic and therapeutic compositions capable of preventing and treating viral-induced tumors in mammals without either destroying healthy uninfected tissue, causing significant systemic side effects, causing scarring or disfigurement of, and/or discomfort to, the mammal treated therewith, and which results in the destruction of latent viral DNA which may be maintained in surrounding tissues, so that instances of incomplete resolution and frequent recurrences of the tumors are reduced. It can further be seen that there also remains a need for methods for providing such prophylactic and therapeutic compositions, as well as methods for the use of such a prophylactic and therapeutic compositions for the prevention and treatment of viral-induced tumors in mammals.